Electrode for building up of steel articles

ABSTRACT

Powdered carbide electrodes for building up of steel articles having high wear resistance of the built-up metal are composed of a nickel sheath and a core containing chromium carbides, e.g. Cr3C2 and 1-3 percent of aluminum powder, based on the overall weight of the electrode. The core may also contain 1-3 percent by weight of the electrode of sodium fluosilicate to eliminate porosity in the built-up layer and chromium boride, boron carbide or boron-chromium alloys to strengthen the matrix (binder) of the deposited metal.

United States Patent lnventors Jury Arsenievich Juzvenko bulvar Lesi Ukrainki, 2, kv. 59, Kiev; Tamara Vladimirovna Lamina, ulitsa Likhachevn, 8b, kv. 7, Kiev; Vasily Plvlovich Shimanovsky, ulitsa Klevsky spusk, 4, kv. 38, Kiev; Vasily Antonovich Gavrish, ulitsa Kapetanovskaya, 6, kv. 10, Kiev; Mark Antonovich Paschenko, ulitsa Ezhena Potie, 9, kv. 97, Kiev; Alexandr Vasilievich Melnik, ulitsa Lenina, 9, kv. I 1, Kiev; Igor Sergeevich Zhurkovsky, ulitsa Kossiora, 6, kv. 29, Dnepropetrovsk; Moisei Isaakovich Vaksin, ulitsa F runze,

1 l, kv. 3, Dnepropetrovsk, all of, U.S.S.R.

Appl. No. Filed Patented Priority June 24, 1969 Sept. 7, 1971 June 28, 1968 U.S.S.R. 1254046 ELECTRODE FOR BUILDING UP OF STEEL ARTICLES 7 Claims, 2 Drawing Figs.

US. Cl. I

Primary ExaminerJ. V. Truhe Assistant Examiner1.awrence A. Rouse AttorneyWaters, Roditi, Schwartz & Nissen ABSTRACT: Powdered carbide electrodes for building up of steel articles having high wear resistance of the built-up metal are composed of a nickel sheath and a core containing chromium carbides, e.g. Cr C and l-3 percent of aluminum powder, based on the overall weight of the electrode. The core may also contain l-3 percent by weight of the electrode of sodium fluosilicate to eliminate porosity in the built-up layer and chromium boride, boron carbide or boron-chromium alloys to strengthen the matrix (binder) of the deposited metal.

PATENIEDSEP nan F/GJa I 20 30 40 50 ea 70 Fl 6.lb

Edition FOR BUILDING UP or STEEL ARTICLES The present invention relates to materials for welding and building up and, more specifically. electrodes to be used for building up of steel articles.

The present invention is particularly useful for building up the parts to be subjected to abrasive wear at normal and elevated temperatures.

Practical experience has shown the alloys containing a high percentage of hard carbides to be exceptionally wear-resistant, and the building up of the aforesaid alloys is generally effected by using tubular electrodes having a nickel or cobalt sheath and a core that contains cast tungsten carbides and rarely other carbides, e.g. chromium carbides.

To build up wear-resistant alloys containing a high percentage of carbides, extensive use is also made of rods manufactured from sinteredalloys, e.g. Cr,C -Ni alloy, which contains 85 percent Cr,C, and, percent Ni (cf. Svarochnoye Proizvodstvo, No. 6, 1965).

Tubular electrodes with a tungsten carbide core fail to provide for the uniform distribution of carbides in the built-up layer, since tungsten carbides are of high specific gravity. Attempts have been made to increase the content of carbides in the built-up layer by using a thin sheath in the known electrodes, but this route results in inferior strength characteristics of the electrode sheath, so that the electrodes in question are unsuitable for use in the form of coils and cannotbe fed reliably into the are zone whemrecourse is had to mechanized building up techniques. 7

Sintered alloy rods make for an increased content of carhides in the built-up layer but are poorly suited for mechanized building up. Sintered electrodes are difficult or impossible to make intocoils of wire.

It is an object of the present invention to eliminate the aforementioned disadvantages.

It is the main object of the invention to provide an electrode having a core composition that will make it possible to attain high wear resistance of the built-up metal at a moderate amount of carbides contained therein. This object is accomplished'by the provision of a powdered carbide electrode for building up of steel articles which comprises a nickel sheath and a core that contains chromium carbides, e.g. Cr C wherein, according to the invention, the electrode core also contains 1-3 weight percent of aluminum powder.

In order to eliminate porosity in the built-up layer, the core of the present electrode additionally contains 1-3 weight percent-of sodium fluosilicate (N a SiF To strengthen the matrix (binder) of the deposited metal, the electrode core also containschromium boride, or boron carbide, or else boron-chromium alloys.

Optimum results are attained :where use is made of theelectrode containing the following proportions of the aforesaid components, percent based on the electrode weight:

chromium carbide (Cr,C,) 40-60 aluminum powder 1-3 sodium fluosilicate 1-3 chromiumboride or boron carbide 2-8 nickel sheath balance.

However, in order to make the present electrode cheaper and simplify its manufacture, it is expedient to take the following proportions of the aforesaid components, percent based on the electrode weight:

chromium carbide (Cr,C,) 40-60 aluminum powder. 1-3 sodium fluosilicaIe 1-3 B-Cr-Fe-Al alloy( lS-ZSZ'B; 30-50%Cr;

2-8; A1; Fe. balance) 2-12 nickel sheath balance The present invention is illustrated hereinbelow by a detained description thereof.

It is pertinent that the sheath material and the carbide exhibit, on being fused, minimum mutual solubility, which property is conducive to obtaining in the built-up layer a maximum content of carbides.

To attain this object, the electrode sheath is made from nickel, while the carbide used is chromium carbide (Cr C An adequately rigid and strong sheath can be obtained provided its weight equals 30-40 percent of the overall electrode weight, but the built-up layer through the agency of such an electrode would contain a significant percentage of soft nickel matrix and an insufficient amount of carbides. The thusbuiltup layer undergoes nonuniform wear, the soft component of the alloy being worn out first, so that the carbides contained therein become exposed and chipped. Hence, the built-up layer produced by means of such electrode exhibits inferior wear resistance.

This drawback can be eliminated by improving the strength characteristics of the soft component (matrix) of the alloy.

To do so, the electrode core contains, apart from chromium carbide, also aluminum, so that in the built-up layer the matrix contains an intermetallic compound, Ni Al, which is instrumental in imparting additional strength to the matrix. A still more substantial strengthening of the matrix, which consists of a nickel-base alloy, results from the employment of borides. With this object in view, powdered chromium boride or boron carbide is also incorporated into the electrode core. Use can also bemade of powdered B-Cr-Al-Fe alloy having the following analysis: 15-25 percent B, 30-50 percent Cr, 2-8 percent Al, the balance being iron. This alloy can be readily ground and is cheaperthan chromium boride or boron carbide.

Listedin Table l are relevant data which illustrate the effect obtained by strengthening the matrix in the built-up metal.

Table l Built-up metal hardness Building up conditions Average Microhardness,

hardness kgJmm.

Matrix Carbides kgJmm.

Building up by manual are technique with a rod from sintered alloy Cr C Building up by automatic submerged arc technique with an electrode containing 59% Cr,C,; 1% Na,SiF and Building up by automatic submerged arc technique with an electrode containing 55% Cr,C 3% Al; 41% Ni and 1% Na,SiF, 42-45 320-400 2,000- 2.200

Building up by automatic submerged arc technique with an electrode containing 51% and 8% of boron-chromium alloy (analysis, see above) 55-58 552-662 2,000- 2,200

It follows from Table 1 that the incorporation of aluminum and boron-containing components into the electrode core enhances the microhardness of the matrix with hard chromium carbides distributed therein.

Wear tests were conducted by blowing specimens with a gas stream containing weight percent of abrasive particles, the abrasives used being quartz sand or flue dust, under the following conditions: specimen temperature, 400 C.; gas pressure ahead of nozzle, 2 atm.; angle of attack (angle at which the abrasive material strikes the surface being tested), 10, 30, 45, and 75; duration of test, minutes.

FlGS. la and lb present graphically the results of tests, FIG. 1a relates to tests with quartz sand as abrasive, and FIG. lb, to tests with flue dust. Curve 1 shows the dependence of abrasive wear of built-up layer of carbon steel (0.45 percent C) on the angle of attack. Curve 2 is the abrasive wear vs angle of attack" graph for built-up high-chromium cast-iron (3.0-3.5 percent C; 25-30 percent Cr; 2-4 percent Ni; 2-4 percent Si, and 0.8-l .5 percent Mn).

Curve 3 is the abrasive wear vs angle of attack" graph for the metal built up by the core electrode consisting of a nickel sheath (40 percent) and a chromium carbide powder core (60 percent).

Curve 4 represents abrasive wear of the metal deposited by means of sintered alloy rod (85 percent CR C and 15 percent Ni) as a function of the angle of attack.

Curve 5 is the abrasive wear vs. angle of attack" graph for the metal deposited by means of the electrode of the present invention.

The experimental data are indicative of the face that the electrodes, according to the invention, provide for high wear resistance of the built-up metal and are not inferior to rods made from a sintered alloy containing 85 percent Cr C- To eliminate porosity in the built-up metal, the electrode core contains 1-3 weight percent of sodium fluosilicate (Na SiF other electrode components being taken in amounts that are conductive to imparting maximum wear resistance to and minimizing the brittleness of the built-up layer. Where boron-containing components are present in excessive amounts, the number and size of cracks will be increased, while a decreased percentage of boron-containing components results in inferior wear resistance of the built-up layer.

For a better understanding of the present invention, tabulated below are the exemplary analysis of the electrodes according to the invention.

former case the sheath should consist of a nickel band having a cross section of, say, 0.3X22 mm., while in the latter case use is made of two bands 0.3X22 mm. and 0.3X24 mm. in dia.

What is claimed is:

1. An electrode for building up of steel parts which comprises a nickel sheath and core containing chromium carbides, and l-3 weight percent of aluminum powder based on the overall weight of the electrode.

10 2. An electrode as claimed in claim I, in which the core contains additionally l-3 weight percent of sodium fluosilicate (Na SiF 3. An electrode as claimed in claim 2, in which the core also contains chromium boride.

l5 4. An electrode as claimed in claim 3, in which the aforesaid electrode components are taken in the following percentages based on the overall weight of the electrode:

chromium carbide (Cr,C,) 40-60 aluminum powder l-3 sodium fluosilicate 3 chromium boride 2-8 nickel sheath balance.

5. An electrode as claimed in claim 7, in which the aforesaid electrode components are taken in the following percentages based on the overall weight of the electrode:

chromium carbide (Cr;,C,) 40-60 aluminum powder l3 sodium fluosilicate l-3 B-Cr-Fc-Al alloy 15-25% B; 30-50% Cr;

2-87: Al; Fe balance) 2-l 2 nickel sheath balance 6. An electrode as claimed in claim 2, in which the core also contains boron carbide.

TABLE 2 Content of components. weight percent Electrode Composition Chromium Chromium Boron Aluminium Nickel Ser. N o. carbide boride carbide Alloy 1 powder NB-zSiFo sheath 1. 5 2. 0 Balance.

1 15-25% B; 30-50% Gr; 28% Al: Fe-balance.

The electrodes may be made in the form of either round wire 5-6 mm. in dia. or band 20X3 mm. in cross section. In the 

1. An electrode for building up of steel parts which comprises a nickel sheath and core containing chromium carbides, and 1-3 weight percent of aluminum powder based on the overall weight of the electrode.
 2. An electrode as claimed in claim 1, in which the core contains additionally 1-3 weight percent of sodium fluosilicate (Na2SiF6).
 3. An electrode as claimed in claim 2, in which the core also contains chromium boride.
 4. An electrode as claimed in claim 3, in which the aforesaid electrode components are taken in the following percentages based on the overall weight of the electrode: chromium carbide (Cr3C2) 40-60 aluminum powder 1-3 sodium fluosilicate 1-3 chromium boride 2-8 nickel sheath balance.
 5. An electrode as claimed in claim 7, in which the aforesaid electrode components are taken in the following percentages based on the overall weight of the electrode: chromium carbide (Cr3C2) 40-60 aluminum powder 1-3 sodium fluosilicate 1-3 B-Cr-Fe-Al alloy (15-25% B; 30-50% Cr; 2-8% Al; Fe-balance) 2-12 nickel sheath balance
 6. An electrode as claimed in claim 2, in which the core also contains boron carbide.
 7. An electrode as claimed in claim 2, in which the core also contains a boron-chromium alloy. 